Method and apparatus for manufacturing a helically finned heat exchanger

ABSTRACT

A method and apparatus is disclosed for the manufacture of a continuous heat exchanger tube including helically winding a spine fin material on the outer wall of a base tube member. A preselected portion of the spine fin material is secured against movement relative to the base tube member. The heat exchanger is then severed in the secured portion so that a section of the secured portion is arranged at each end of the severed heat exchanger. The secured severed end sections are effective in maintaining the intermediate portion of the spine fin material from unwinding and, as a result, in heat transfer relationship with the base tube member.

llnited States Patent [1 1 Hicks METHOD AND APPARATUS FOR MANUFACTURING A HELICALLY F INNED HEAT EXCHANGER Y [52] U.S. Cl...... 29/l57.3 AH; 29/202 D; 29/202 R; 29/417; 113/1 C; 156/269 [51] lint. Cl? B21D 53/02; B23P 15/26 [58] Field of Search... 29/l57.3 AH, 202 D, 202 R, 29/417, DIG. l; 113/1 C; 156/187, 269

[56] References Cited UNITED STATES PATENTS 1,216,657 2/1917 Cardell 29/202 D 1,893,523 l/l933 Radzinsky 156/269 2,095,599 10/1937 Gleason et al. 29/417 X Primary ExaminerC. W. Lanham Assistant ExaminerD. C. Reiley, Ill

[57 ABSTRACT A method and apparatus is disclosed for the manufacture of a continuous heat exchanger tube including helically winding a spine fin material on the outer wall of a base tube member. A preselected portion of the spine fin material is secured against movement relative to the base tube member. The heat exchanger is then severed in the secured portion so that a section of the secured portion is arranged at each end of the severed heat exchanger. The secured severed end sections are effective in maintaining the intermediate portion of the spine fin material from unwinding and, as a result, in heat transfer relationship with the base tube memher.

8 Claims, 4 Drawing Figures METHOD AND APPARATUS FOR MANUFACTURING A HELICALLY FINNED I-EAT EXCHANGER BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to the provision for manufacturing a continuous heat exchanger tube including helically winding a spine fin material formed to include a flange which is arranged in intimate contact with the outer wall of a base tube member and, more specifically, to the provision of securing a preselected portion of the spine fin material against movement relative to the base member. The heat exchanger is severed in the secured portion so that a section of the secured portion is arranged at each end of the cut length of each heat exchanger. The secured end sections arranged on each end of the heat exchanger are effective in maintaining the intermediate portions of the spine fin material in its original helically wound position.

2. Description of the Prior Art In the manufacture of spine fin heat exchangers, it has been customary to use spine fin material of dissimilar metal than the base tube member, for example, the spine fin material has been fabricated of aluminum, while the base tube member has been copper. This use of dissimilar metals has resulted in galvanic corrosion of the relatively thin spine fin material. To overcome the problem of the galvanic corrosion and the resultant loss of spine fin material, an adhesive material has been applied between the flange of the spine fin material and the outer wall of the base tube member in amounts sufficient to prevent direct contact between the aluminum and copper to prevent galvanic corrosion, while at the same time maintaining adequate heat transfer between them. While it was necessary to provide a complete film of adhesive between the contacting surfaces of dissimilar metals to prevent galvanic corrosion, it would not be required between similar metals since galvanic corrosion would not be a major factor. For example, if the base tube member was aluminum, it could be of the type that would have minimum reaction to the aluminum of the spine fin material. However, it should be noted that in the manufacture of continuous spine fin material by machines such as the one shown and described in US. Pat. No. 3,005,253-Venables assigned to the General Electric Company, assignee of the present invention, wherein the fabricated spine fin heat exchanger is cut into predetermined lengths during the.

manufacturing and winding operations, the lack of means for securing the spine fin material against movement relative to the base tube member would cause the spine fin material to start unwinding from its loose ends and thereby lose its heat transfer advantages.

It is therefore an object of the present invention to provide the spine fin heat exchanger where selected portions of the spine fin material are secured against movement relative to the base tube member in a manner affective to prevent the other portion of the spine fin material from moving relative to the base tube member.

SUMMARY OF THE INVENTION According to the present invention, there is provided a method and apparatus for manufacturing from a continuous heat exchanger a predetermined length of spine fin heat exchanger having a spine fin material helically wound on a base tube member and being secured at each end of the predetermined length. The spine fin material is wound on the base tube member as it is being advanced at a preselected speed so that the spine fin material is in intimate contact with adjacent wraps and the outer wall of the tube member. A preselected portion of the spine fin material at spaced intervals on the spine fin heat exchanger are secured against movement relative to the base tube member. Finally, the spine fin heat exchanger is severed in the secured portion to form the predetermined lengths of the heat exchanger with the secured cut portions forming end por tions that are held against movement relative to said base tube member and that are effective to maintain the intermediate portion of the spine fin material in its initial helically wound position.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of an apparatus for fabricating a heat exchanger in accordance with one embodiment of the invention;

FIG. 2 is a schematic view of the heat exchanger formed according to the preferred embodiment of the present invention;

FIG. 3 shows a heat exchanger fabricated in accordance with another embodiment of the invention; and

FIG. 4 shows a heat exchanger fabricated in accordance with still another embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION In the embodiment of FIG. 1, a continuous spine fin heat exchanger 10 of the type having a continuous spine fin material 12 is helically wound on a base tube member 14. The details of construction of an automatic machine 16 that may be employed in fabricating the present invention is shown and described in US. Pat. No. 3,005,253Venab1es, assigned to the General Electric Company, the assignee of the present invention. A suitable base tube member 14 is fed vertically upward by feeding means 18 through the machine 16. A rotating support table 20 is arranged for rotation about a vertical axis. The table 20 carries a coil of sheet stock 21 which is fabricated into the spine fin material 12 as well as the fin wrapping and forming assembly 22.

In operation the tube base member 12 is fed through an axial passage in the rotating support table 20 and past the fin wrapping and forming assembly 22. The forming assembly includes means for bending the strip stock to form a base flange 24 and for lancing the strip to form fin sections 25. The wrapping assembly includes means for helically winding the spine fin material 12 onto the base tube member 14 as it advances through the machine 16 under tension so that the base flange 24 is in intimate heat transfer contact with outer tube wall. During the continuous wrapping operation, the fabricated spine fin heat exchanger 10 is cut into predetermined lengths 1 1 to be formed into condensors or evaporators to be used in refrigeration systems. The means for severing the heat exchanger may include a cutting or severing station 27 that may be activated after the heat exchanger 10 reaches a predetermined length. In fabricating heat exchangers wherein the base tube member and spine fin material were of dissimilar materials as in the case of employing a copper tube and aluminum spine fin material resulted in galvanic corrosion. To alleviate this problem, adhesive was used between the aluminum spine fin material and the copper tube to prevent their contact while maintaining adequate heat transfer between the two. The use of a base tube and spine fin of similar material wherein aluminum tubing is employed for use with aluminum Spine fin material does not require that adhesive or other material to be used between them to prevent galvanic corrosion as in the case of dissimilar metals. It should be noted, however, that the unsecured spine fin material 12 at the ends of the severed heat exchanger would unwrap from the base tube member 14 if the spine fin material was not secured against movement relative to the base tube member.

Accordingly, a method and apparatus are provided by the present invention to secure preselected portions of spine fin material 12 against movement relative to the base tube member 14. Referring to FIGS. 1 and 2, the preselected portions of the heat exchanger 10 of the spine fin material 12 that is secured against movement relative to the base tube member 14 is designated A. Control or sensing means 26 may be provided at a convenient location to accurately control the length of portion A and the distance between them and to activate the cutting station 29 so that the heat exchanger 10 is severed substantially at the midpoint of portion A. While it is critical to the present invention that the heat exchanger 10 is cut within the portion A, the exact location or construction of the control or sensing means 26 for activating the cutting station 29 may be optional. For purposes of simplicity, the control or sensing means 26 has been shown schematically at the inlet or tube receiving end of the machine 16. Referring to FIG. 2, it will be apparent that the severed sections of portion A form the end portion of each cut section 11 of heat exchanger 10 wherein the spine fin material 12 is secured against movement relative to the base tube member 14. The secured portions A at each end of the cut heat exchanger are effective in maintaining the tension wrapped intermediate portion of spine fin material designated B in FIG. 4 in its initial helically wound heat transfer position.

The means for securing the portion A against movement relative to the tube 14 may be a coating of adhesive 27 applied to preselected sections of the tube as it advances through the machine. Referring to the embodiment shown in FIG. 1, the adhesive may be applied by a dispensing means 28 arranged between the feeding means 18 and the forming assembly 22. The dispensing means 28 may be activated by the control means 26 which, in turn, may monitor the advancing tube 14. The dispensing means 28 under control of means 26 cffectively applies adhesive 27 to the base tube 14 at preselected intervals and for a predetermined length to provide portion A so that the spine fin material 12 engaging the adhesive is secured against movement relative to the base tube 14. In effect, only the spine fin material 12 arranged in the portion A of the heat exchanger 10 is secured to the base tube member 14 which as hereinbefore noted is effective in maintaining the portion B in its original helically wound position.

The cutting station 29, while shown arranged in close proximity to the machine 16, may be located in other convenient locations, and like the dispensing means 28, the cutting station 29 may be activated by the control means 26. While it is not critical in what manner the station 29 is activated, it is, however, necessary as previously explained that the heat exchanger 10 be severed in the secured portion A to form the lengths 11.

In another embodiment of the invention as shown in FIG. 3, the means for securing the spine fin material 12 relative to the base tube member 14 in portion A employs the use of an adhesive or bonding material that is applied over the spine fin material 12 after the forming and wrapping operations. In accordance with this embodiment, a sufficient amount of adhesive is applied so that the spine fins of adjacent wraps are encapsulated or joined together as one unit so that the unwinding of severed or cut end of portion A is prevented.

In still another embodiment of the invention as shown in FIG. 4, means for securing the spine fin material 12 relative to the base tube member 14 in portion A includes deforming the fin sections 25 of adjacent wraps of the spine fin material so that they interlock together to form a unit effective in preventing the unwinding of the severed or cut end of portion A.

Modifications of this invention will occur to those skilled in this art. Therefore, it is to be understood that this invention is not limited to the particular embodiment disclosed, but that it is intended to cover all modifications which are within the true spirit and scope of this invention as claimed.

I claim:

1. Method of manufacturing a continuous spine fin heat exchanger tube including a spine fin material supported on a base tube member which comprises:

helically winding said spine fin material in intimate contact with adjacent wraps and the outer wall of said tube;

securing a preselected portion of said spine fin material at spaced intervals on said spine fin heat exchanger so as to prevent movement thereof relative to said base tube member;

severing said heat exchanger in said preselected portion to form predetermined lengths of said heat exchanger with said preselected portions forming end portions effectively held against movement relative to said base tube member so that the other portion of said helically wound spine fin material intermediate said preselected portion is maintained in its initial helically wound position.

2. A method as set forth in claim 1, wherein the spine fin material in the preselected portion is secured against movement relative to the base tube member by applying adhesive to the outer wall of the base tube prior to said winding step.

3. A method as set forth in claim-1, wherein the spine fin material in the preselected portion is secured against movement relative to the base tube member by applying a bonding means on said spine fin material after said winding step that is sufficient to bond adjacent wraps of said spine fin material.

4. A method as set forth in claim 3, wherein said bonding means encapsulates adjacent wraps of the spine fin material in said preselected area.

5. An apparatus for manufacturing a continuous spine fin heat exchanger tube including a spine fin material supported on a base tube member which comprises:

means advancing said base tube member at a preselected rate of speed;

means helically winding said spine fin material in intimate contact with adjacent wraps and the outer wall of said advancing tube to form said spine fin heat exchanger;

means securing a preselected portion of said spine fin material at spaced intervals along the advancing spine fin heat exchanger so as to prevent movement thereof relative to said base tube member;

means severing said advancing heat exchanger in said preselected portion to form predetermined lengths of said heat exchanger with said preselected portion forming end portions effectively held against movement relative to said base tube member so that the other portion of said helically wound spine fin material intermediate said preselected portion is maintained in its initial helically wound position.

6. The apparatus according to claim 5 wherein said means advancing said tube include control means associated therewith for activating said securing means and said severing means at preselected times during the manufacture of said spine fin heat exchanger.

7. The apparatus according to claim 6 wherein the means securing said preselected portion of said spine fin material includes means for applying adhesive to said base tube member in said preselected portionprior to wrapping the spine fin material on said tube base member.

8. The apparatus according to claim 6 wherein the means securing said preselected portion of said spine fin material includes means for depositing an amount of adhesive sufficient to bond adjacent wraps of said spine fin material in said portion prior to severing said heat exchanger into predetermined lengths. 

1. Method of manufacturing a continuous spine fin heat exchanger tube including a spine fin material supported on a base tube member which comprises: helically winding said spine fin material in intimate contact with adjacent wraps and the outer wall of said tube; securing a preselected portion of said spine fin material at spaced intervals on said spine fin heat exchanger so as to prevent movement thereof relative to said base tube member; severing said heat exchanger in said preselected portion to form predetermined lengths of said heat exchanger with said preselected portions forming end portions effectively held against movement relative to said base tube member so that the other portion of said helically wound spine fin material intermediate said preselected portion is maintained in its initial helically wound position.
 2. A method as set forth in claim 1, wherein the spine fin material in the preselected portion is secured against movement relative to the base tube member by applying adhesive to the outer wall of the base tube prior to said winding step.
 3. A method as set forth in claim 1, wherein the spine fin material in the preselected portion is secured against movement relative to the base tube member by applying a bonding means on said spine fin material after said winding step that is sufficient to bond adjacent wraps of said spine fin material.
 4. A method as set forth in claim 3, wherein said bonding means encapsulates adjacent wraps of the spine fin material in said preselected area.
 5. An apparatus for manufacturing a continuous spine fin heat exchanger tube including a spine fin material supported on a base tube member which comprises: means advancing said base tube member at a preselected rate of speed; means helically winding said spine fin material in intimate contact with adjacent wraps and the outer wall of said advancing tube to form said spine fin heat exchanger; means securing a preselected portion of said spine fin material at spaced intervals along the advancing spine fin heat exchanger so as to prevent movement thereof relative to said base tube member; means severing said advancing heat exchanger in said preselected portion to form predetermined lengths of said heat exchanger with said preselected portion forming end portions effectively held against movement relative to said base tube member so that the other portion of said helically wound spine fin material intermediate said preselected portion is maintained in its initial helically wound position.
 6. The apparatus according to claim 5 wherein said means advancing said tube include control means associated therewith for activating said securing means and said severing means at preselected times during the manufacture of said spine fin heat exchanger.
 7. The apparatus according to claim 6 wherein the means securing said preselected portion of said spine fin material includes means for applying adhesive to said base tube member in said preselected portion prior to wrapping the spine fin material on said tube base member.
 8. The apparatus according to claim 6 wherein the means securing said preselected portion of said spine fin material includes means for depositing an amount of adhesive sufficient to bond adjacent wraps of said spine fin material in said portion prior to severing said heat exchanger into predetermined lengths. 